If you are registering Typos which is certainly not my specialist area, you need to know whether it is an error that is generally made.
No Overture would suggest that in this case it is not. There are more sophisticated systems used by others that will give you a better answer, but in general I would leave this to those that know what they are doing.
Note, some of the supposedly high traffic Typos for sale in the secondary market may be nothing more than a Scam. It is not difficult to creat Traffic Records or even Overture for utterly worthless domains.
Best Regards
Dave Wrixon